<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
    <input v-model="score">
    <div v-if="score>=90">优秀</div>
    <div v-else-if="score>=80 && score<90">良好</div>
    <div v-else-if="score>=60 && score<80">一般</div>
    <div v-else>较差</div>

    <div v-show="flag">123</div>
    <input type="button" v-on:click="handle" value="切换">
</div>

<script>
    var app=new Vue({
        el:'#app',
        data:{
            score:90,
            flag:true,
        },
        methods:{
            handle:function(){
                this.flag=!this.flag;
            }
        }
    })
</script>

</body>
</html>